High potential transformer



5 Sheets-Sheet l IIIIIIII Illllllllllln' 4470 #Se n t t :i

Feb. 20, 1934. F. J. FISCHER HIGH POTENTAL TRANSFORMER Filed April 25, 1950 KAM M Feb. 20, 1934. F. J. FISCHER HIGH POTENTIAL TRANSFORMER Fiied April 2s, 1930 3 Sheets-Sheet 2 on c... OO

Il! i Feb. 20, 1934. F. J. FISCHER 1,948,417

HIGH POTENTIAL TRANSFORMER Y Filed April 23. 1930 5 Sheets-Sheet 3 QN l Patented Feb. 20, 1934 PATENT OFFICE 1,948,417 HIGH POTENTIAL TRANSFORMER Franz Joseph Fischer, Dresden,

Sterzel' Aktiengesellschaft,

signor to Koch & Dresden, Germany, a

Application nd in Germany 8 Claims.

The invention relates to a high potential transformer, in particular a potential measuring transformer which is distinguished by specially small dimensions as compared with previous constructions. Y,

The invention consists in that the high potential winding of the transformer is so arranged in layers in a single part coil spool, similar to a yarn spool, oinsulating material, that only the end lo of the innermost winding layer carrying the high potential has to be carried out through the flange of the coil spool, and the low potential end of the winding is situated outside on the winding circumference.

The ywinding extends over the whole axial length of the coil spool and the layer ends rest on the flange of the coil spool. The highest potential of the innermost winding layer is graduated in stages up to the externally situated initial or earth potential, by the potentials of the winding layers as arranged. Creeping discharges on the flange of the coil spool are impossible, as a positive potential lis impressed at each point by the adjacent winding. Care has therefore only to be taken that the end windings of each layer are wound close up to the flange, so that between the i end windings of the layers and the flange of the coil spool, there is little'or no air pocket formation which might give rise to ionization phenomena. The outer layer of the high potential winding carries approximately earth potential, and has therefore practically no potential' as compared with the adjacent earth parts. As a protection, the high potential winding is surrounded by a casing which may be of insulating material or metal .and fit close to the winding. All surfaces` with the exception of the ilange surfaces on which the layer ends rest, are coated with a conductive layer which is produced by metallizing, graphiting, or painting with a conductive varnish. Of the conductive layers separated from each other by the flange surfaces, the layer covered by the high potential winding is electrically connected with the potential of the innermost layer 45 of the high potential winding. This coating forms, with the conductive layer on the inside o! the coil spool bore and that on the outer sides of the ilange and the metal covering, a condenser as capacitative bridging of the high potentialwinding. Excess voltage waves coming along are flattened and potential jumps inside the winding are reduced to a minimum, so that this transformer construction approximates to the ideal condi, ti

The end of` the high potential winding is car- Germany, as-

German company April 23, 1930, Serial No. 446,622,

April 30, 1929 ried out through a lead-out insulator which forms one piece with the coil spool. The lead-out here lies in the extension of the outlet aperture of the high potential winding end through the coilv spool flange and is therefore eccentric to the trans- 6.0 former axis.

Fig. 1 shows a section through the high potential transformer with open iron core opposite the lead-out insulator. v

Fig. 2 is a diagram of the conductive parts on 65 the high potential transformer omitting the parts of insulating material for the insulation of the high potential winding.

In Fig. 3 is shown a section through the high potential transformer with iron core covered op` 70 posite the leadout insulator.

Fig. 4 is a section through the high potential transformer with a double limbed iron core.

In Fig. 5 the high potential transformer is arranged in an ordinary oil vessel with lead-out insulator separated from the coil spool of the high potential winding.

In Fig. 6 is shown the high potential transformer for the suspension and support of the high potenial line itself to which it is to be connected.

According to Fig. 7, two high potential windings are wound in two single part coil spools joined together.

Fig. 8 'shows the suspension of two high potential transformers on their casings, partly in sec- B5 tion and partly in elevation, for carrying the high potential conductor.

Fig. 9 gives a vertical section through the arrangement of two high potential transformers which are supported on their cores and which also carry the high potential line.

Fig. 10 shows the arrangement of two high potential transformers on a common iron core in stationary form of construction, by vertical section. y

Fig. 1 shows a section through the coil spool 11 having approximately the shape of a yarn spool, and the high potential winding 12 wound in layers in the coil spool. All gaps or hollow spaces between the windings and the coil spool are filled with impregnating medium such as varnish, bakelite, or the like. Each wound layer may also be painted and the winding litted in the coil spool be impregnated under vacuum and the action of heat. On the iron core 13 surrounding the coil spool, is arrangedthe low potential winding 14 which together with the core is concentrically surrounded byv the tube shaped part 15 of the coil spool. The flanges 16 of the coil spool are made thinner towards the outside corresponding to the no downward graduation of potential of the ends of the layers resting on the inner fiange surfaces. The lead-out 17 is arranged eccentrically to the central axis of the coil spool, and a conductor 18 leads from its connection terminals to the commencement of the high potential winding. The other end 12a of the high potential winding is conductively connected with the metal casing 19 or with the core 13 surrounding the high potential winding, and is put on earth potential. The casing 19 is so wide that it projects a little over the high potential winding on both sides and rests on the flange 16 of the coil spool. It has in section the form of the coil spool flange orA of the winding and completely surrounds the winding. All surfaces of the coil spool, with the exception of those upon which the ends of the layers of the high potential Winding rest, are metallized, graphited or painted with conductive varnish. An ionization of the air due to the difference of the dielectric constants of the insulating material 0f the coil spool as compared with air, is thereby prevented. The metallized surface 20 is, corresponding to the section of the coil spool tube, mostly cylindrical, and this cylinder in order to avoid the formation of a short circuit winding is slit in the longitudinal axis. The surface 20 is conductivelyconnected with the commencement of the high potential winding, while the metallized surfaces 21 of the inside of the coil spool tube 15 and of the outside of the flange 16 and the split metal casing 19 are electrically connected with the iron core and also with earth.

From Fig. 2 will be seen the capacitive substitute diagram of the high potential side of the transformer. The inner metallizing 20 connected with the high potential represents one condenser coating which is' surrounded by the other condenser coating consisting of the e'arth metallizing of the outer surface 21 of the coil spool and the metal casing 19. The high potential winding 12 arranged between the metallizing 20 and the outer metal casing 19 is capacitively bridged over by this condenser so formed.

Fig. 3 again represents the same section as in Fig. 1 through the transformer, only with the difference that here the core yoke 24 extending over the upper ange of the spool is surrounded by an extension of an inverted U-shape which is placed with its limbs upon the upper coil spool iiange and is connected integrally therewith and with the insulator 17. The passage thus formed, which is open at both sides, extends over the entire width of the coil spool flange 16. The eccentrically situated lead-out 17 resting on this extension contains a high potential safety fuse 27. The mount 28 of the lead-out is so formed that the connection 29 to the high potential conductor takes place eccentrically to the central axis of the lead-out, in order to permit a convenient replacement of the safety fuse 27. The casing 19 surrounding the high potential winding is bent at its upper end round the flange 16 of the coil spool and fixed at its lower end on to the foot 30 of the transformer by means of attachment devices.

In Fig. 4, differently from Fig. 3, the lead-out 17 is placed in the central axis of the transformer. In the extension 26 surrounding the core yoke 24 and forming the passage 25, a channel 31 is provided in its closed end in which is carried the connecting wire from the lead-out 17 to the commencement of the high potential winding. Here instead of thethree limbed casing core, a two limbed iron core is shown, so that the passage 25 only needs to be opened at one end. At the same time, this figure shows the sunken construction of the high potential transformer in a wall, floor or ceiling, this taking place by means o! a flange 32 fixed on the casing 19.

Fig. 5 shows that the lead-out need not always form one piece with the coil spool 11, but may be independently arranged as a connector leadout 22 on the cover of a transformer chamber 23. Here the connecting rod 18 is insulated by the insulating material in the chamber, from the earth parts, and the flange surface round the lead-out point is not made conductive.

In Fig. 6 the 'lower flange 16 of the coil spool is provided with projecting ribs 35 and the bore 31 for carrying out the high potential end of the high potential winding into the insulator 17. is directed towards the centre as in Fig. 4. The high potential conductor itself is held at the end of the insulator l-y means of a grip. The iron core is again carried out through a passage 25 as in Figure 4 from the inside of the coil spool. The lower end of the casing 19 engages round the flange 16, and the upper end is fixed to a conductive carrier cap 33 which is connected to earth by a metallic supporting device. This iigure only shows one transformer of suspension construction. Any number of such transformers could, however, be so suspended between themselves that instead of the high potential conductor, a further carrier cap of the next transformer could be fixed, and so on. A form of transformer suspension chain would then be produced.

In Fig. 7 is shown a section through the transformer produced by the combination of two coil spools according to Fig. 2 into one piece. The high potential windings are dividedfby the eentral rib 34 into two halves, and connected with their outermost ends to the earth casing 19, so that the transformer formed by these two high potential windings is capable of double pole connection.

Fig. 8 shows a suspension arrangement under one another of two transformers constructed essentially according to Fig. 1. A band 38 placed round the casing 19 carries each transformer as well as the next transformer through a suspension insulator member 39. The lead-out 17 is ibent over by to the transformer axis, and

serves for leadingout one or more layer potentials of the high potential winding for the time being, through conductors, to the next transformer.

In Fig. 9 are shown two high potential transformers with horizontal iron cores 13 suspended by supporting devices 36. In this case, there are insulators 17 provided on both sides of the coil spool bent over on the flanges by 90 to the axisof the coils, which insulators serve to support the next transformer or the high potential conductor. To increase the spark-over potential, the insulators maybe provided with metal or porcelain shields. The supportingy devices 36 serve at the same time as electric connections.

From the high potential connection, the line runs through the high potential winding of the lower system, the casing surrounding it, through the left-hand supporting device, through the high potential winding of the upper system, its casing and the other left-hand supporting device, to earth. The ends of the low potential winding of the lower system are connected to the two supporting devices of the iron core of this system, and the one supporting device is fixed, insulated at the point 37, to the iron core. This low potenf insulators .17 in a base plate.

, upper system,

' there is produced from -innermost layer of y of theupper transformer system, and both transtial winding works in conjunction with the first the high potential winding mitr the output from the lower to the up'per system.

A Fig.A 10 shows a standing arrangement of two, transformers on a vertical iron core 40 in which only the upper transformer hasone of the separate systems described.. Thelower transformer carries externally the high potential, and internally yearth potential. The .iron core 40 is held by the lower coil spool, which is fixed by its two The upper coil spool has onlyone insulator 17, and is arranged on the other limb of the iron core. From the high potential connection, the line runs through the high potential winding to the casing 19 of the from here through the iron core to the casing 19 of the lower system, and from there through the high potential winding to earth. The casing of the upper and the casing of the lower systems are each independently split and the free ends are so connected together that the two a band winding lying round the high potential coils. This winding then transmits the output from the upper system to the lower one, `and is known by the name of an over-coupling winding. The low potential winding 4l rests in the lower coil spool on the. metallizing 20. Its connections are carried out through the other insulator of the lower coil spool.

The low potential winding may, with the transformers described, be also fitted externally round the high potential winding 12. In the latter case, the coil spool 1l is made smaller since the high potential winding comes closer to the iron core. The coil spool ,can beround or angular corresponding to the shape of the winding. The hollow spaces between coil spools' and earthed parts of the transformer are preferably filled with sand.

What I claim and desire to secure by Letters Patent of the United States is:-

1. A high potential transformer with a single part coil spool of insulating material having the shape of a yarn spool, a highpotential winding wound in layers in the coil spool over its whole axial length and the layer ends of which rest on the coil spool flange, a lead-out of the inner layer end through the flange of the coil\spool and through an insulator combined in onev part with the coil spool flange and carrying at its end the high potential connection, said high potential connection situated eccentrically to the axis of the insulating medium, aconnection of the outeriayer end to the earth, an iron core which is carried through the coil spool bore and a low potential winding.

2. A high potential transformer with a single part coil spool of insulating material, a high potential winding wound in' layers in the coil.

spool over its whole axial length and the layer f ends of which rest on the coil spool flange, a.

lead-out of the inner layer end through the flange of the coil spool and through an insulator combined in one part with the coil spool flange carrying at its end the high potential connection and arranged in the centre axis of the trans-v former to the high potential connection, a connection of the outer layer end to the earth, an.

iron core which is carried through thecoil spool bore and a low potential winding.

3. A high potential transformer with a single part coil spool-of insulating material, a high potential winding wound in layers in the coil spool over its whole axial length, and the layer ends of which rest on the coil spool flange, a lead-out of the inner layer end through the flange of the coil spool to the high potential connection, a connectionv of the outer layer end to the earth, an iron core which is carried through the coil spool bore, a low potential winding, and an oil chamber with high and low-potential leadout insulators in the cover.

4. A high potential transformer with a single part coil spool of insulating material, a high potential winding wound in layers in the coil spool over its whole axial length, and the layer ends of which rest on the coil casing electrically interrupted and mechanically held together surrounding the outer layer of the high potential winding and parts of the flanges, a lead-out of the inner end through the flange of the coil spool to the high potential connection, a connection of the outer layer end on to the metal casing, an iron core which is carried through the coil spool bore, a low potential winding and a connection of the metal casing and of the ironcore with earth potential and a suspension device fixed on the casing.

5. A high potential transformer with a single part coil spool of insulating material, a high potential winding wound in layers in the coil spool over its whole axial length, and the layer ends of which rest on the coil spool flange, a leadout of the inner layer end through the one flange of the coil spool and through an insulator combined in one piece with the coil spool flange and carrying at its end the high potential connection to the high potential connection, a seclond lead-out for a tapping on a winding layer through the other flange of the coil spool to a second connection, a connection of the outer layer end on to the earth, an iron core which is carried through the coil spool bore, fastening parts for the iron core and a low potential winding.

5. A high potential transformer with a single part coilspool of insulating material, a vhigh potential winding wound in layers in the coil spool over its whole axial length, and the layer spool flange, a metal' the iron core, and a low potential winding, conductive holding devices fixed on the insulators for a similar second high potential transformer, an insulation of the holding devices from each other on the iron core of the second transformer and connections on the holding devices for the low potential winding and the high potential winding of the second transformer.

7. In a high potential transformer for measuringq high voltages comprising a coil spool of insulating material having tapered end flanges, a high vpotential winding wound in layers on the coil spool and extendingthe length thereof, an oil container cover associated with the transformer and a substantially bell-shaped lead-out member mounted on said cover, the end of the winding extending through the flange of the coil insulator mounted on one of the flanged ends of the coilspool, said lead extending through said insulator, the connection oi' the end of the outervmost winding laver having such a distribution that the commencement oi the winding receives thehighest potential and the end a. constant zero or earth potential so that the potentials oi the windings at the flanges increase from the outer periphery of the high tension winding towards the inside.

FRANZ JOSEPH FISCHER. 

